Adding upstream version 13.4.upstream/13.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1487 insertions, 0 deletions

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
new file mode 100644
index 0000000..c55dc14
--- /dev/null
+++ b/src/include/pgstat.h
@@ -0,0 +1,1487 @@
+/* ----------
+ *	pgstat.h
+ *
+ *	Definitions for the PostgreSQL statistics collector daemon.
+ *
+ *	Copyright (c) 2001-2020, PostgreSQL Global Development Group
+ *
+ *	src/include/pgstat.h
+ * ----------
+ */
+#ifndef PGSTAT_H
+#define PGSTAT_H
+
+#include "datatype/timestamp.h"
+#include "libpq/pqcomm.h"
+#include "miscadmin.h"
+#include "port/atomics.h"
+#include "portability/instr_time.h"
+#include "postmaster/pgarch.h"
+#include "storage/proc.h"
+#include "utils/hsearch.h"
+#include "utils/relcache.h"
+
+
+/* ----------
+ * Paths for the statistics files (relative to installation's $PGDATA).
+ * ----------
+ */
+#define PGSTAT_STAT_PERMANENT_DIRECTORY		"pg_stat"
+#define PGSTAT_STAT_PERMANENT_FILENAME		"pg_stat/global.stat"
+#define PGSTAT_STAT_PERMANENT_TMPFILE		"pg_stat/global.tmp"
+
+/* Default directory to store temporary statistics data in */
+#define PG_STAT_TMP_DIR		"pg_stat_tmp"
+
+/* Values for track_functions GUC variable --- order is significant! */
+typedef enum TrackFunctionsLevel
+{
+	TRACK_FUNC_OFF,
+	TRACK_FUNC_PL,
+	TRACK_FUNC_ALL
+}			TrackFunctionsLevel;
+
+/* ----------
+ * The types of backend -> collector messages
+ * ----------
+ */
+typedef enum StatMsgType
+{
+	PGSTAT_MTYPE_DUMMY,
+	PGSTAT_MTYPE_INQUIRY,
+	PGSTAT_MTYPE_TABSTAT,
+	PGSTAT_MTYPE_TABPURGE,
+	PGSTAT_MTYPE_DROPDB,
+	PGSTAT_MTYPE_RESETCOUNTER,
+	PGSTAT_MTYPE_RESETSHAREDCOUNTER,
+	PGSTAT_MTYPE_RESETSINGLECOUNTER,
+	PGSTAT_MTYPE_RESETSLRUCOUNTER,
+	PGSTAT_MTYPE_AUTOVAC_START,
+	PGSTAT_MTYPE_VACUUM,
+	PGSTAT_MTYPE_ANALYZE,
+	PGSTAT_MTYPE_ARCHIVER,
+	PGSTAT_MTYPE_BGWRITER,
+	PGSTAT_MTYPE_SLRU,
+	PGSTAT_MTYPE_FUNCSTAT,
+	PGSTAT_MTYPE_FUNCPURGE,
+	PGSTAT_MTYPE_RECOVERYCONFLICT,
+	PGSTAT_MTYPE_TEMPFILE,
+	PGSTAT_MTYPE_DEADLOCK,
+	PGSTAT_MTYPE_CHECKSUMFAILURE
+} StatMsgType;
+
+/* ----------
+ * The data type used for counters.
+ * ----------
+ */
+typedef int64 PgStat_Counter;
+
+/* ----------
+ * PgStat_TableCounts			The actual per-table counts kept by a backend
+ *
+ * This struct should contain only actual event counters, because we memcmp
+ * it against zeroes to detect whether there are any counts to transmit.
+ * It is a component of PgStat_TableStatus (within-backend state) and
+ * PgStat_TableEntry (the transmitted message format).
+ *
+ * Note: for a table, tuples_returned is the number of tuples successfully
+ * fetched by heap_getnext, while tuples_fetched is the number of tuples
+ * successfully fetched by heap_fetch under the control of bitmap indexscans.
+ * For an index, tuples_returned is the number of index entries returned by
+ * the index AM, while tuples_fetched is the number of tuples successfully
+ * fetched by heap_fetch under the control of simple indexscans for this index.
+ *
+ * tuples_inserted/updated/deleted/hot_updated count attempted actions,
+ * regardless of whether the transaction committed.  delta_live_tuples,
+ * delta_dead_tuples, and changed_tuples are set depending on commit or abort.
+ * Note that delta_live_tuples and delta_dead_tuples can be negative!
+ * ----------
+ */
+typedef struct PgStat_TableCounts
+{
+	PgStat_Counter t_numscans;
+
+	PgStat_Counter t_tuples_returned;
+	PgStat_Counter t_tuples_fetched;
+
+	PgStat_Counter t_tuples_inserted;
+	PgStat_Counter t_tuples_updated;
+	PgStat_Counter t_tuples_deleted;
+	PgStat_Counter t_tuples_hot_updated;
+	bool		t_truncated;
+
+	PgStat_Counter t_delta_live_tuples;
+	PgStat_Counter t_delta_dead_tuples;
+	PgStat_Counter t_changed_tuples;
+
+	PgStat_Counter t_blocks_fetched;
+	PgStat_Counter t_blocks_hit;
+} PgStat_TableCounts;
+
+/* Possible targets for resetting cluster-wide shared values */
+typedef enum PgStat_Shared_Reset_Target
+{
+	RESET_ARCHIVER,
+	RESET_BGWRITER
+} PgStat_Shared_Reset_Target;
+
+/* Possible object types for resetting single counters */
+typedef enum PgStat_Single_Reset_Type
+{
+	RESET_TABLE,
+	RESET_FUNCTION
+} PgStat_Single_Reset_Type;
+
+/* ------------------------------------------------------------
+ * Structures kept in backend local memory while accumulating counts
+ * ------------------------------------------------------------
+ */
+
+
+/* ----------
+ * PgStat_TableStatus			Per-table status within a backend
+ *
+ * Many of the event counters are nontransactional, ie, we count events
+ * in committed and aborted transactions alike.  For these, we just count
+ * directly in the PgStat_TableStatus.  However, delta_live_tuples,
+ * delta_dead_tuples, and changed_tuples must be derived from event counts
+ * with awareness of whether the transaction or subtransaction committed or
+ * aborted.  Hence, we also keep a stack of per-(sub)transaction status
+ * records for every table modified in the current transaction.  At commit
+ * or abort, we propagate tuples_inserted/updated/deleted up to the
+ * parent subtransaction level, or out to the parent PgStat_TableStatus,
+ * as appropriate.
+ * ----------
+ */
+typedef struct PgStat_TableStatus
+{
+	Oid			t_id;			/* table's OID */
+	bool		t_shared;		/* is it a shared catalog? */
+	struct PgStat_TableXactStatus *trans;	/* lowest subxact's counts */
+	PgStat_TableCounts t_counts;	/* event counts to be sent */
+} PgStat_TableStatus;
+
+/* ----------
+ * PgStat_TableXactStatus		Per-table, per-subtransaction status
+ * ----------
+ */
+typedef struct PgStat_TableXactStatus
+{
+	PgStat_Counter tuples_inserted; /* tuples inserted in (sub)xact */
+	PgStat_Counter tuples_updated;	/* tuples updated in (sub)xact */
+	PgStat_Counter tuples_deleted;	/* tuples deleted in (sub)xact */
+	bool		truncated;		/* relation truncated in this (sub)xact */
+	PgStat_Counter inserted_pre_trunc;	/* tuples inserted prior to truncate */
+	PgStat_Counter updated_pre_trunc;	/* tuples updated prior to truncate */
+	PgStat_Counter deleted_pre_trunc;	/* tuples deleted prior to truncate */
+	int			nest_level;		/* subtransaction nest level */
+	/* links to other structs for same relation: */
+	struct PgStat_TableXactStatus *upper;	/* next higher subxact if any */
+	PgStat_TableStatus *parent; /* per-table status */
+	/* structs of same subxact level are linked here: */
+	struct PgStat_TableXactStatus *next;	/* next of same subxact */
+} PgStat_TableXactStatus;
+
+
+/* ------------------------------------------------------------
+ * Message formats follow
+ * ------------------------------------------------------------
+ */
+
+
+/* ----------
+ * PgStat_MsgHdr				The common message header
+ * ----------
+ */
+typedef struct PgStat_MsgHdr
+{
+	StatMsgType m_type;
+	int			m_size;
+} PgStat_MsgHdr;
+
+/* ----------
+ * Space available in a message.  This will keep the UDP packets below 1K,
+ * which should fit unfragmented into the MTU of the loopback interface.
+ * (Larger values of PGSTAT_MAX_MSG_SIZE would work for that on most
+ * platforms, but we're being conservative here.)
+ * ----------
+ */
+#define PGSTAT_MAX_MSG_SIZE 1000
+#define PGSTAT_MSG_PAYLOAD	(PGSTAT_MAX_MSG_SIZE - sizeof(PgStat_MsgHdr))
+
+
+/* ----------
+ * PgStat_MsgDummy				A dummy message, ignored by the collector
+ * ----------
+ */
+typedef struct PgStat_MsgDummy
+{
+	PgStat_MsgHdr m_hdr;
+} PgStat_MsgDummy;
+
+
+/* ----------
+ * PgStat_MsgInquiry			Sent by a backend to ask the collector
+ *								to write the stats file(s).
+ *
+ * Ordinarily, an inquiry message prompts writing of the global stats file,
+ * the stats file for shared catalogs, and the stats file for the specified
+ * database.  If databaseid is InvalidOid, only the first two are written.
+ *
+ * New file(s) will be written only if the existing file has a timestamp
+ * older than the specified cutoff_time; this prevents duplicated effort
+ * when multiple requests arrive at nearly the same time, assuming that
+ * backends send requests with cutoff_times a little bit in the past.
+ *
+ * clock_time should be the requestor's current local time; the collector
+ * uses this to check for the system clock going backward, but it has no
+ * effect unless that occurs.  We assume clock_time >= cutoff_time, though.
+ * ----------
+ */
+
+typedef struct PgStat_MsgInquiry
+{
+	PgStat_MsgHdr m_hdr;
+	TimestampTz clock_time;		/* observed local clock time */
+	TimestampTz cutoff_time;	/* minimum acceptable file timestamp */
+	Oid			databaseid;		/* requested DB (InvalidOid => shared only) */
+} PgStat_MsgInquiry;
+
+
+/* ----------
+ * PgStat_TableEntry			Per-table info in a MsgTabstat
+ * ----------
+ */
+typedef struct PgStat_TableEntry
+{
+	Oid			t_id;
+	PgStat_TableCounts t_counts;
+} PgStat_TableEntry;
+
+/* ----------
+ * PgStat_MsgTabstat			Sent by the backend to report table
+ *								and buffer access statistics.
+ * ----------
+ */
+#define PGSTAT_NUM_TABENTRIES  \
+	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - 3 * sizeof(int) - 2 * sizeof(PgStat_Counter))	\
+	 / sizeof(PgStat_TableEntry))
+
+typedef struct PgStat_MsgTabstat
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	int			m_nentries;
+	int			m_xact_commit;
+	int			m_xact_rollback;
+	PgStat_Counter m_block_read_time;	/* times in microseconds */
+	PgStat_Counter m_block_write_time;
+	PgStat_TableEntry m_entry[PGSTAT_NUM_TABENTRIES];
+} PgStat_MsgTabstat;
+
+
+/* ----------
+ * PgStat_MsgTabpurge			Sent by the backend to tell the collector
+ *								about dead tables.
+ * ----------
+ */
+#define PGSTAT_NUM_TABPURGE  \
+	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - sizeof(int))  \
+	 / sizeof(Oid))
+
+typedef struct PgStat_MsgTabpurge
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	int			m_nentries;
+	Oid			m_tableid[PGSTAT_NUM_TABPURGE];
+} PgStat_MsgTabpurge;
+
+
+/* ----------
+ * PgStat_MsgDropdb				Sent by the backend to tell the collector
+ *								about a dropped database
+ * ----------
+ */
+typedef struct PgStat_MsgDropdb
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+} PgStat_MsgDropdb;
+
+
+/* ----------
+ * PgStat_MsgResetcounter		Sent by the backend to tell the collector
+ *								to reset counters
+ * ----------
+ */
+typedef struct PgStat_MsgResetcounter
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+} PgStat_MsgResetcounter;
+
+/* ----------
+ * PgStat_MsgResetsharedcounter Sent by the backend to tell the collector
+ *								to reset a shared counter
+ * ----------
+ */
+typedef struct PgStat_MsgResetsharedcounter
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_Shared_Reset_Target m_resettarget;
+} PgStat_MsgResetsharedcounter;
+
+/* ----------
+ * PgStat_MsgResetsinglecounter Sent by the backend to tell the collector
+ *								to reset a single counter
+ * ----------
+ */
+typedef struct PgStat_MsgResetsinglecounter
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	PgStat_Single_Reset_Type m_resettype;
+	Oid			m_objectid;
+} PgStat_MsgResetsinglecounter;
+
+/* ----------
+ * PgStat_MsgResetslrucounter Sent by the backend to tell the collector
+ *								to reset a SLRU counter
+ * ----------
+ */
+typedef struct PgStat_MsgResetslrucounter
+{
+	PgStat_MsgHdr m_hdr;
+	int			m_index;
+} PgStat_MsgResetslrucounter;
+
+/* ----------
+ * PgStat_MsgAutovacStart		Sent by the autovacuum daemon to signal
+ *								that a database is going to be processed
+ * ----------
+ */
+typedef struct PgStat_MsgAutovacStart
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	TimestampTz m_start_time;
+} PgStat_MsgAutovacStart;
+
+
+/* ----------
+ * PgStat_MsgVacuum				Sent by the backend or autovacuum daemon
+ *								after VACUUM
+ * ----------
+ */
+typedef struct PgStat_MsgVacuum
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	Oid			m_tableoid;
+	bool		m_autovacuum;
+	TimestampTz m_vacuumtime;
+	PgStat_Counter m_live_tuples;
+	PgStat_Counter m_dead_tuples;
+} PgStat_MsgVacuum;
+
+
+/* ----------
+ * PgStat_MsgAnalyze			Sent by the backend or autovacuum daemon
+ *								after ANALYZE
+ * ----------
+ */
+typedef struct PgStat_MsgAnalyze
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	Oid			m_tableoid;
+	bool		m_autovacuum;
+	bool		m_resetcounter;
+	TimestampTz m_analyzetime;
+	PgStat_Counter m_live_tuples;
+	PgStat_Counter m_dead_tuples;
+} PgStat_MsgAnalyze;
+
+
+/* ----------
+ * PgStat_MsgArchiver			Sent by the archiver to update statistics.
+ * ----------
+ */
+typedef struct PgStat_MsgArchiver
+{
+	PgStat_MsgHdr m_hdr;
+	bool		m_failed;		/* Failed attempt */
+	char		m_xlog[MAX_XFN_CHARS + 1];
+	TimestampTz m_timestamp;
+} PgStat_MsgArchiver;
+
+/* ----------
+ * PgStat_MsgBgWriter			Sent by the bgwriter to update statistics.
+ * ----------
+ */
+typedef struct PgStat_MsgBgWriter
+{
+	PgStat_MsgHdr m_hdr;
+
+	PgStat_Counter m_timed_checkpoints;
+	PgStat_Counter m_requested_checkpoints;
+	PgStat_Counter m_buf_written_checkpoints;
+	PgStat_Counter m_buf_written_clean;
+	PgStat_Counter m_maxwritten_clean;
+	PgStat_Counter m_buf_written_backend;
+	PgStat_Counter m_buf_fsync_backend;
+	PgStat_Counter m_buf_alloc;
+	PgStat_Counter m_checkpoint_write_time; /* times in milliseconds */
+	PgStat_Counter m_checkpoint_sync_time;
+} PgStat_MsgBgWriter;
+
+/* ----------
+ * PgStat_MsgSLRU			Sent by a backend to update SLRU statistics.
+ * ----------
+ */
+typedef struct PgStat_MsgSLRU
+{
+	PgStat_MsgHdr m_hdr;
+	PgStat_Counter m_index;
+	PgStat_Counter m_blocks_zeroed;
+	PgStat_Counter m_blocks_hit;
+	PgStat_Counter m_blocks_read;
+	PgStat_Counter m_blocks_written;
+	PgStat_Counter m_blocks_exists;
+	PgStat_Counter m_flush;
+	PgStat_Counter m_truncate;
+} PgStat_MsgSLRU;
+
+/* ----------
+ * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
+ * ----------
+ */
+typedef struct PgStat_MsgRecoveryConflict
+{
+	PgStat_MsgHdr m_hdr;
+
+	Oid			m_databaseid;
+	int			m_reason;
+} PgStat_MsgRecoveryConflict;
+
+/* ----------
+ * PgStat_MsgTempFile	Sent by the backend upon creating a temp file
+ * ----------
+ */
+typedef struct PgStat_MsgTempFile
+{
+	PgStat_MsgHdr m_hdr;
+
+	Oid			m_databaseid;
+	size_t		m_filesize;
+} PgStat_MsgTempFile;
+
+/* ----------
+ * PgStat_FunctionCounts	The actual per-function counts kept by a backend
+ *
+ * This struct should contain only actual event counters, because we memcmp
+ * it against zeroes to detect whether there are any counts to transmit.
+ *
+ * Note that the time counters are in instr_time format here.  We convert to
+ * microseconds in PgStat_Counter format when transmitting to the collector.
+ * ----------
+ */
+typedef struct PgStat_FunctionCounts
+{
+	PgStat_Counter f_numcalls;
+	instr_time	f_total_time;
+	instr_time	f_self_time;
+} PgStat_FunctionCounts;
+
+/* ----------
+ * PgStat_BackendFunctionEntry	Entry in backend's per-function hash table
+ * ----------
+ */
+typedef struct PgStat_BackendFunctionEntry
+{
+	Oid			f_id;
+	PgStat_FunctionCounts f_counts;
+} PgStat_BackendFunctionEntry;
+
+/* ----------
+ * PgStat_FunctionEntry			Per-function info in a MsgFuncstat
+ * ----------
+ */
+typedef struct PgStat_FunctionEntry
+{
+	Oid			f_id;
+	PgStat_Counter f_numcalls;
+	PgStat_Counter f_total_time;	/* times in microseconds */
+	PgStat_Counter f_self_time;
+} PgStat_FunctionEntry;
+
+/* ----------
+ * PgStat_MsgFuncstat			Sent by the backend to report function
+ *								usage statistics.
+ * ----------
+ */
+#define PGSTAT_NUM_FUNCENTRIES	\
+	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - sizeof(int))  \
+	 / sizeof(PgStat_FunctionEntry))
+
+typedef struct PgStat_MsgFuncstat
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	int			m_nentries;
+	PgStat_FunctionEntry m_entry[PGSTAT_NUM_FUNCENTRIES];
+} PgStat_MsgFuncstat;
+
+/* ----------
+ * PgStat_MsgFuncpurge			Sent by the backend to tell the collector
+ *								about dead functions.
+ * ----------
+ */
+#define PGSTAT_NUM_FUNCPURGE  \
+	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - sizeof(int))  \
+	 / sizeof(Oid))
+
+typedef struct PgStat_MsgFuncpurge
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	int			m_nentries;
+	Oid			m_functionid[PGSTAT_NUM_FUNCPURGE];
+} PgStat_MsgFuncpurge;
+
+/* ----------
+ * PgStat_MsgDeadlock			Sent by the backend to tell the collector
+ *								about a deadlock that occurred.
+ * ----------
+ */
+typedef struct PgStat_MsgDeadlock
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+} PgStat_MsgDeadlock;
+
+/* ----------
+ * PgStat_MsgChecksumFailure	Sent by the backend to tell the collector
+ *								about checksum failures noticed.
+ * ----------
+ */
+typedef struct PgStat_MsgChecksumFailure
+{
+	PgStat_MsgHdr m_hdr;
+	Oid			m_databaseid;
+	int			m_failurecount;
+	TimestampTz m_failure_time;
+} PgStat_MsgChecksumFailure;
+
+
+/* ----------
+ * PgStat_Msg					Union over all possible messages.
+ * ----------
+ */
+typedef union PgStat_Msg
+{
+	PgStat_MsgHdr msg_hdr;
+	PgStat_MsgDummy msg_dummy;
+	PgStat_MsgInquiry msg_inquiry;
+	PgStat_MsgTabstat msg_tabstat;
+	PgStat_MsgTabpurge msg_tabpurge;
+	PgStat_MsgDropdb msg_dropdb;
+	PgStat_MsgResetcounter msg_resetcounter;
+	PgStat_MsgResetsharedcounter msg_resetsharedcounter;
+	PgStat_MsgResetsinglecounter msg_resetsinglecounter;
+	PgStat_MsgResetslrucounter msg_resetslrucounter;
+	PgStat_MsgAutovacStart msg_autovacuum_start;
+	PgStat_MsgVacuum msg_vacuum;
+	PgStat_MsgAnalyze msg_analyze;
+	PgStat_MsgArchiver msg_archiver;
+	PgStat_MsgBgWriter msg_bgwriter;
+	PgStat_MsgSLRU msg_slru;
+	PgStat_MsgFuncstat msg_funcstat;
+	PgStat_MsgFuncpurge msg_funcpurge;
+	PgStat_MsgRecoveryConflict msg_recoveryconflict;
+	PgStat_MsgDeadlock msg_deadlock;
+	PgStat_MsgTempFile msg_tempfile;
+	PgStat_MsgChecksumFailure msg_checksumfailure;
+} PgStat_Msg;
+
+
+/* ------------------------------------------------------------
+ * Statistic collector data structures follow
+ *
+ * PGSTAT_FILE_FORMAT_ID should be changed whenever any of these
+ * data structures change.
+ * ------------------------------------------------------------
+ */
+
+#define PGSTAT_FILE_FORMAT_ID	0x01A5BC9D
+
+/* ----------
+ * PgStat_StatDBEntry			The collector's data per database
+ * ----------
+ */
+typedef struct PgStat_StatDBEntry
+{
+	Oid			databaseid;
+	PgStat_Counter n_xact_commit;
+	PgStat_Counter n_xact_rollback;
+	PgStat_Counter n_blocks_fetched;
+	PgStat_Counter n_blocks_hit;
+	PgStat_Counter n_tuples_returned;
+	PgStat_Counter n_tuples_fetched;
+	PgStat_Counter n_tuples_inserted;
+	PgStat_Counter n_tuples_updated;
+	PgStat_Counter n_tuples_deleted;
+	TimestampTz last_autovac_time;
+	PgStat_Counter n_conflict_tablespace;
+	PgStat_Counter n_conflict_lock;
+	PgStat_Counter n_conflict_snapshot;
+	PgStat_Counter n_conflict_bufferpin;
+	PgStat_Counter n_conflict_startup_deadlock;
+	PgStat_Counter n_temp_files;
+	PgStat_Counter n_temp_bytes;
+	PgStat_Counter n_deadlocks;
+	PgStat_Counter n_checksum_failures;
+	TimestampTz last_checksum_failure;
+	PgStat_Counter n_block_read_time;	/* times in microseconds */
+	PgStat_Counter n_block_write_time;
+
+	TimestampTz stat_reset_timestamp;
+	TimestampTz stats_timestamp;	/* time of db stats file update */
+
+	/*
+	 * tables and functions must be last in the struct, because we don't write
+	 * the pointers out to the stats file.
+	 */
+	HTAB	   *tables;
+	HTAB	   *functions;
+} PgStat_StatDBEntry;
+
+
+/* ----------
+ * PgStat_StatTabEntry			The collector's data per table (or index)
+ * ----------
+ */
+typedef struct PgStat_StatTabEntry
+{
+	Oid			tableid;
+
+	PgStat_Counter numscans;
+
+	PgStat_Counter tuples_returned;
+	PgStat_Counter tuples_fetched;
+
+	PgStat_Counter tuples_inserted;
+	PgStat_Counter tuples_updated;
+	PgStat_Counter tuples_deleted;
+	PgStat_Counter tuples_hot_updated;
+
+	PgStat_Counter n_live_tuples;
+	PgStat_Counter n_dead_tuples;
+	PgStat_Counter changes_since_analyze;
+	PgStat_Counter inserts_since_vacuum;
+
+	PgStat_Counter blocks_fetched;
+	PgStat_Counter blocks_hit;
+
+	TimestampTz vacuum_timestamp;	/* user initiated vacuum */
+	PgStat_Counter vacuum_count;
+	TimestampTz autovac_vacuum_timestamp;	/* autovacuum initiated */
+	PgStat_Counter autovac_vacuum_count;
+	TimestampTz analyze_timestamp;	/* user initiated */
+	PgStat_Counter analyze_count;
+	TimestampTz autovac_analyze_timestamp;	/* autovacuum initiated */
+	PgStat_Counter autovac_analyze_count;
+} PgStat_StatTabEntry;
+
+
+/* ----------
+ * PgStat_StatFuncEntry			The collector's data per function
+ * ----------
+ */
+typedef struct PgStat_StatFuncEntry
+{
+	Oid			functionid;
+
+	PgStat_Counter f_numcalls;
+
+	PgStat_Counter f_total_time;	/* times in microseconds */
+	PgStat_Counter f_self_time;
+} PgStat_StatFuncEntry;
+
+
+/*
+ * Archiver statistics kept in the stats collector
+ */
+typedef struct PgStat_ArchiverStats
+{
+	PgStat_Counter archived_count;	/* archival successes */
+	char		last_archived_wal[MAX_XFN_CHARS + 1];	/* last WAL file
+														 * archived */
+	TimestampTz last_archived_timestamp;	/* last archival success time */
+	PgStat_Counter failed_count;	/* failed archival attempts */
+	char		last_failed_wal[MAX_XFN_CHARS + 1]; /* WAL file involved in
+													 * last failure */
+	TimestampTz last_failed_timestamp;	/* last archival failure time */
+	TimestampTz stat_reset_timestamp;
+} PgStat_ArchiverStats;
+
+/*
+ * Global statistics kept in the stats collector
+ */
+typedef struct PgStat_GlobalStats
+{
+	TimestampTz stats_timestamp;	/* time of stats file update */
+	PgStat_Counter timed_checkpoints;
+	PgStat_Counter requested_checkpoints;
+	PgStat_Counter checkpoint_write_time;	/* times in milliseconds */
+	PgStat_Counter checkpoint_sync_time;
+	PgStat_Counter buf_written_checkpoints;
+	PgStat_Counter buf_written_clean;
+	PgStat_Counter maxwritten_clean;
+	PgStat_Counter buf_written_backend;
+	PgStat_Counter buf_fsync_backend;
+	PgStat_Counter buf_alloc;
+	TimestampTz stat_reset_timestamp;
+} PgStat_GlobalStats;
+
+/*
+ * SLRU statistics kept in the stats collector
+ */
+typedef struct PgStat_SLRUStats
+{
+	PgStat_Counter blocks_zeroed;
+	PgStat_Counter blocks_hit;
+	PgStat_Counter blocks_read;
+	PgStat_Counter blocks_written;
+	PgStat_Counter blocks_exists;
+	PgStat_Counter flush;
+	PgStat_Counter truncate;
+	TimestampTz stat_reset_timestamp;
+} PgStat_SLRUStats;
+
+
+/* ----------
+ * Backend states
+ * ----------
+ */
+typedef enum BackendState
+{
+	STATE_UNDEFINED,
+	STATE_IDLE,
+	STATE_RUNNING,
+	STATE_IDLEINTRANSACTION,
+	STATE_FASTPATH,
+	STATE_IDLEINTRANSACTION_ABORTED,
+	STATE_DISABLED
+} BackendState;
+
+
+/* ----------
+ * Wait Classes
+ * ----------
+ */
+#define PG_WAIT_LWLOCK				0x01000000U
+#define PG_WAIT_LOCK				0x03000000U
+#define PG_WAIT_BUFFER_PIN			0x04000000U
+#define PG_WAIT_ACTIVITY			0x05000000U
+#define PG_WAIT_CLIENT				0x06000000U
+#define PG_WAIT_EXTENSION			0x07000000U
+#define PG_WAIT_IPC					0x08000000U
+#define PG_WAIT_TIMEOUT				0x09000000U
+#define PG_WAIT_IO					0x0A000000U
+
+/* ----------
+ * Wait Events - Activity
+ *
+ * Use this category when a process is waiting because it has no work to do,
+ * unless the "Client" or "Timeout" category describes the situation better.
+ * Typically, this should only be used for background processes.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_ARCHIVER_MAIN = PG_WAIT_ACTIVITY,
+	WAIT_EVENT_AUTOVACUUM_MAIN,
+	WAIT_EVENT_BGWRITER_HIBERNATE,
+	WAIT_EVENT_BGWRITER_MAIN,
+	WAIT_EVENT_CHECKPOINTER_MAIN,
+	WAIT_EVENT_LOGICAL_APPLY_MAIN,
+	WAIT_EVENT_LOGICAL_LAUNCHER_MAIN,
+	WAIT_EVENT_PGSTAT_MAIN,
+	WAIT_EVENT_RECOVERY_WAL_STREAM,
+	WAIT_EVENT_SYSLOGGER_MAIN,
+	WAIT_EVENT_WAL_RECEIVER_MAIN,
+	WAIT_EVENT_WAL_SENDER_MAIN,
+	WAIT_EVENT_WAL_WRITER_MAIN
+} WaitEventActivity;
+
+/* ----------
+ * Wait Events - Client
+ *
+ * Use this category when a process is waiting to send data to or receive data
+ * from the frontend process to which it is connected.  This is never used for
+ * a background process, which has no client connection.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_CLIENT_READ = PG_WAIT_CLIENT,
+	WAIT_EVENT_CLIENT_WRITE,
+	WAIT_EVENT_GSS_OPEN_SERVER,
+	WAIT_EVENT_LIBPQWALRECEIVER_CONNECT,
+	WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE,
+	WAIT_EVENT_SSL_OPEN_SERVER,
+	WAIT_EVENT_WAL_RECEIVER_WAIT_START,
+	WAIT_EVENT_WAL_SENDER_WAIT_WAL,
+	WAIT_EVENT_WAL_SENDER_WRITE_DATA,
+} WaitEventClient;
+
+/* ----------
+ * Wait Events - IPC
+ *
+ * Use this category when a process cannot complete the work it is doing because
+ * it is waiting for a notification from another process.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_BACKUP_WAIT_WAL_ARCHIVE = PG_WAIT_IPC,
+	WAIT_EVENT_BGWORKER_SHUTDOWN,
+	WAIT_EVENT_BGWORKER_STARTUP,
+	WAIT_EVENT_BTREE_PAGE,
+	WAIT_EVENT_CHECKPOINT_DONE,
+	WAIT_EVENT_CHECKPOINT_START,
+	WAIT_EVENT_EXECUTE_GATHER,
+	WAIT_EVENT_HASH_BATCH_ALLOCATE,
+	WAIT_EVENT_HASH_BATCH_ELECT,
+	WAIT_EVENT_HASH_BATCH_LOAD,
+	WAIT_EVENT_HASH_BUILD_ALLOCATE,
+	WAIT_EVENT_HASH_BUILD_ELECT,
+	WAIT_EVENT_HASH_BUILD_HASH_INNER,
+	WAIT_EVENT_HASH_BUILD_HASH_OUTER,
+	WAIT_EVENT_HASH_GROW_BATCHES_ALLOCATE,
+	WAIT_EVENT_HASH_GROW_BATCHES_DECIDE,
+	WAIT_EVENT_HASH_GROW_BATCHES_ELECT,
+	WAIT_EVENT_HASH_GROW_BATCHES_FINISH,
+	WAIT_EVENT_HASH_GROW_BATCHES_REPARTITION,
+	WAIT_EVENT_HASH_GROW_BUCKETS_ALLOCATE,
+	WAIT_EVENT_HASH_GROW_BUCKETS_ELECT,
+	WAIT_EVENT_HASH_GROW_BUCKETS_REINSERT,
+	WAIT_EVENT_LOGICAL_SYNC_DATA,
+	WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE,
+	WAIT_EVENT_MQ_INTERNAL,
+	WAIT_EVENT_MQ_PUT_MESSAGE,
+	WAIT_EVENT_MQ_RECEIVE,
+	WAIT_EVENT_MQ_SEND,
+	WAIT_EVENT_PARALLEL_BITMAP_SCAN,
+	WAIT_EVENT_PARALLEL_CREATE_INDEX_SCAN,
+	WAIT_EVENT_PARALLEL_FINISH,
+	WAIT_EVENT_PROCARRAY_GROUP_UPDATE,
+	WAIT_EVENT_PROC_SIGNAL_BARRIER,
+	WAIT_EVENT_PROMOTE,
+	WAIT_EVENT_RECOVERY_CONFLICT_SNAPSHOT,
+	WAIT_EVENT_RECOVERY_CONFLICT_TABLESPACE,
+	WAIT_EVENT_RECOVERY_PAUSE,
+	WAIT_EVENT_REPLICATION_ORIGIN_DROP,
+	WAIT_EVENT_REPLICATION_SLOT_DROP,
+	WAIT_EVENT_SAFE_SNAPSHOT,
+	WAIT_EVENT_SYNC_REP,
+	WAIT_EVENT_XACT_GROUP_UPDATE
+} WaitEventIPC;
+
+/* ----------
+ * Wait Events - Timeout
+ *
+ * Use this category when a process is waiting for a timeout to expire.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_BASE_BACKUP_THROTTLE = PG_WAIT_TIMEOUT,
+	WAIT_EVENT_PG_SLEEP,
+	WAIT_EVENT_RECOVERY_APPLY_DELAY,
+	WAIT_EVENT_RECOVERY_RETRIEVE_RETRY_INTERVAL,
+	WAIT_EVENT_VACUUM_DELAY
+} WaitEventTimeout;
+
+/* ----------
+ * Wait Events - IO
+ *
+ * Use this category when a process is waiting for a IO.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_BUFFILE_READ = PG_WAIT_IO,
+	WAIT_EVENT_BUFFILE_WRITE,
+	WAIT_EVENT_CONTROL_FILE_READ,
+	WAIT_EVENT_CONTROL_FILE_SYNC,
+	WAIT_EVENT_CONTROL_FILE_SYNC_UPDATE,
+	WAIT_EVENT_CONTROL_FILE_WRITE,
+	WAIT_EVENT_CONTROL_FILE_WRITE_UPDATE,
+	WAIT_EVENT_COPY_FILE_READ,
+	WAIT_EVENT_COPY_FILE_WRITE,
+	WAIT_EVENT_DATA_FILE_EXTEND,
+	WAIT_EVENT_DATA_FILE_FLUSH,
+	WAIT_EVENT_DATA_FILE_IMMEDIATE_SYNC,
+	WAIT_EVENT_DATA_FILE_PREFETCH,
+	WAIT_EVENT_DATA_FILE_READ,
+	WAIT_EVENT_DATA_FILE_SYNC,
+	WAIT_EVENT_DATA_FILE_TRUNCATE,
+	WAIT_EVENT_DATA_FILE_WRITE,
+	WAIT_EVENT_DSM_FILL_ZERO_WRITE,
+	WAIT_EVENT_LOCK_FILE_ADDTODATADIR_READ,
+	WAIT_EVENT_LOCK_FILE_ADDTODATADIR_SYNC,
+	WAIT_EVENT_LOCK_FILE_ADDTODATADIR_WRITE,
+	WAIT_EVENT_LOCK_FILE_CREATE_READ,
+	WAIT_EVENT_LOCK_FILE_CREATE_SYNC,
+	WAIT_EVENT_LOCK_FILE_CREATE_WRITE,
+	WAIT_EVENT_LOCK_FILE_RECHECKDATADIR_READ,
+	WAIT_EVENT_LOGICAL_REWRITE_CHECKPOINT_SYNC,
+	WAIT_EVENT_LOGICAL_REWRITE_MAPPING_SYNC,
+	WAIT_EVENT_LOGICAL_REWRITE_MAPPING_WRITE,
+	WAIT_EVENT_LOGICAL_REWRITE_SYNC,
+	WAIT_EVENT_LOGICAL_REWRITE_TRUNCATE,
+	WAIT_EVENT_LOGICAL_REWRITE_WRITE,
+	WAIT_EVENT_RELATION_MAP_READ,
+	WAIT_EVENT_RELATION_MAP_SYNC,
+	WAIT_EVENT_RELATION_MAP_WRITE,
+	WAIT_EVENT_REORDER_BUFFER_READ,
+	WAIT_EVENT_REORDER_BUFFER_WRITE,
+	WAIT_EVENT_REORDER_LOGICAL_MAPPING_READ,
+	WAIT_EVENT_REPLICATION_SLOT_READ,
+	WAIT_EVENT_REPLICATION_SLOT_RESTORE_SYNC,
+	WAIT_EVENT_REPLICATION_SLOT_SYNC,
+	WAIT_EVENT_REPLICATION_SLOT_WRITE,
+	WAIT_EVENT_SLRU_FLUSH_SYNC,
+	WAIT_EVENT_SLRU_READ,
+	WAIT_EVENT_SLRU_SYNC,
+	WAIT_EVENT_SLRU_WRITE,
+	WAIT_EVENT_SNAPBUILD_READ,
+	WAIT_EVENT_SNAPBUILD_SYNC,
+	WAIT_EVENT_SNAPBUILD_WRITE,
+	WAIT_EVENT_TIMELINE_HISTORY_FILE_SYNC,
+	WAIT_EVENT_TIMELINE_HISTORY_FILE_WRITE,
+	WAIT_EVENT_TIMELINE_HISTORY_READ,
+	WAIT_EVENT_TIMELINE_HISTORY_SYNC,
+	WAIT_EVENT_TIMELINE_HISTORY_WRITE,
+	WAIT_EVENT_TWOPHASE_FILE_READ,
+	WAIT_EVENT_TWOPHASE_FILE_SYNC,
+	WAIT_EVENT_TWOPHASE_FILE_WRITE,
+	WAIT_EVENT_WALSENDER_TIMELINE_HISTORY_READ,
+	WAIT_EVENT_WAL_BOOTSTRAP_SYNC,
+	WAIT_EVENT_WAL_BOOTSTRAP_WRITE,
+	WAIT_EVENT_WAL_COPY_READ,
+	WAIT_EVENT_WAL_COPY_SYNC,
+	WAIT_EVENT_WAL_COPY_WRITE,
+	WAIT_EVENT_WAL_INIT_SYNC,
+	WAIT_EVENT_WAL_INIT_WRITE,
+	WAIT_EVENT_WAL_READ,
+	WAIT_EVENT_WAL_SYNC,
+	WAIT_EVENT_WAL_SYNC_METHOD_ASSIGN,
+	WAIT_EVENT_WAL_WRITE
+} WaitEventIO;
+
+/* ----------
+ * Command type for progress reporting purposes
+ * ----------
+ */
+typedef enum ProgressCommandType
+{
+	PROGRESS_COMMAND_INVALID,
+	PROGRESS_COMMAND_VACUUM,
+	PROGRESS_COMMAND_ANALYZE,
+	PROGRESS_COMMAND_CLUSTER,
+	PROGRESS_COMMAND_CREATE_INDEX,
+	PROGRESS_COMMAND_BASEBACKUP
+} ProgressCommandType;
+
+#define PGSTAT_NUM_PROGRESS_PARAM	20
+
+/* ----------
+ * Shared-memory data structures
+ * ----------
+ */
+
+
+/*
+ * PgBackendSSLStatus
+ *
+ * For each backend, we keep the SSL status in a separate struct, that
+ * is only filled in if SSL is enabled.
+ *
+ * All char arrays must be null-terminated.
+ */
+typedef struct PgBackendSSLStatus
+{
+	/* Information about SSL connection */
+	int			ssl_bits;
+	bool		ssl_compression;
+	char		ssl_version[NAMEDATALEN];
+	char		ssl_cipher[NAMEDATALEN];
+	char		ssl_client_dn[NAMEDATALEN];
+
+	/*
+	 * serial number is max "20 octets" per RFC 5280, so this size should be
+	 * fine
+	 */
+	char		ssl_client_serial[NAMEDATALEN];
+
+	char		ssl_issuer_dn[NAMEDATALEN];
+} PgBackendSSLStatus;
+
+/*
+ * PgBackendGSSStatus
+ *
+ * For each backend, we keep the GSS status in a separate struct, that
+ * is only filled in if GSS is enabled.
+ *
+ * All char arrays must be null-terminated.
+ */
+typedef struct PgBackendGSSStatus
+{
+	/* Information about GSSAPI connection */
+	char		gss_princ[NAMEDATALEN]; /* GSSAPI Principal used to auth */
+	bool		gss_auth;		/* If GSSAPI authentication was used */
+	bool		gss_enc;		/* If encryption is being used */
+
+} PgBackendGSSStatus;
+
+
+/* ----------
+ * PgBackendStatus
+ *
+ * Each live backend maintains a PgBackendStatus struct in shared memory
+ * showing its current activity.  (The structs are allocated according to
+ * BackendId, but that is not critical.)  Note that the collector process
+ * has no involvement in, or even access to, these structs.
+ *
+ * Each auxiliary process also maintains a PgBackendStatus struct in shared
+ * memory.
+ * ----------
+ */
+typedef struct PgBackendStatus
+{
+	/*
+	 * To avoid locking overhead, we use the following protocol: a backend
+	 * increments st_changecount before modifying its entry, and again after
+	 * finishing a modification.  A would-be reader should note the value of
+	 * st_changecount, copy the entry into private memory, then check
+	 * st_changecount again.  If the value hasn't changed, and if it's even,
+	 * the copy is valid; otherwise start over.  This makes updates cheap
+	 * while reads are potentially expensive, but that's the tradeoff we want.
+	 *
+	 * The above protocol needs memory barriers to ensure that the apparent
+	 * order of execution is as it desires.  Otherwise, for example, the CPU
+	 * might rearrange the code so that st_changecount is incremented twice
+	 * before the modification on a machine with weak memory ordering.  Hence,
+	 * use the macros defined below for manipulating st_changecount, rather
+	 * than touching it directly.
+	 */
+	int			st_changecount;
+
+	/* The entry is valid iff st_procpid > 0, unused if st_procpid == 0 */
+	int			st_procpid;
+
+	/* Type of backends */
+	BackendType st_backendType;
+
+	/* Times when current backend, transaction, and activity started */
+	TimestampTz st_proc_start_timestamp;
+	TimestampTz st_xact_start_timestamp;
+	TimestampTz st_activity_start_timestamp;
+	TimestampTz st_state_start_timestamp;
+
+	/* Database OID, owning user's OID, connection client address */
+	Oid			st_databaseid;
+	Oid			st_userid;
+	SockAddr	st_clientaddr;
+	char	   *st_clienthostname;	/* MUST be null-terminated */
+
+	/* Information about SSL connection */
+	bool		st_ssl;
+	PgBackendSSLStatus *st_sslstatus;
+
+	/* Information about GSSAPI connection */
+	bool		st_gss;
+	PgBackendGSSStatus *st_gssstatus;
+
+	/* current state */
+	BackendState st_state;
+
+	/* application name; MUST be null-terminated */
+	char	   *st_appname;
+
+	/*
+	 * Current command string; MUST be null-terminated. Note that this string
+	 * possibly is truncated in the middle of a multi-byte character. As
+	 * activity strings are stored more frequently than read, that allows to
+	 * move the cost of correct truncation to the display side. Use
+	 * pgstat_clip_activity() to truncate correctly.
+	 */
+	char	   *st_activity_raw;
+
+	/*
+	 * Command progress reporting.  Any command which wishes can advertise
+	 * that it is running by setting st_progress_command,
+	 * st_progress_command_target, and st_progress_param[].
+	 * st_progress_command_target should be the OID of the relation which the
+	 * command targets (we assume there's just one, as this is meant for
+	 * utility commands), but the meaning of each element in the
+	 * st_progress_param array is command-specific.
+	 */
+	ProgressCommandType st_progress_command;
+	Oid			st_progress_command_target;
+	int64		st_progress_param[PGSTAT_NUM_PROGRESS_PARAM];
+} PgBackendStatus;
+
+/*
+ * Macros to load and store st_changecount with appropriate memory barriers.
+ *
+ * Use PGSTAT_BEGIN_WRITE_ACTIVITY() before, and PGSTAT_END_WRITE_ACTIVITY()
+ * after, modifying the current process's PgBackendStatus data.  Note that,
+ * since there is no mechanism for cleaning up st_changecount after an error,
+ * THESE MACROS FORM A CRITICAL SECTION.  Any error between them will be
+ * promoted to PANIC, causing a database restart to clean up shared memory!
+ * Hence, keep the critical section as short and straight-line as possible.
+ * Aside from being safer, that minimizes the window in which readers will
+ * have to loop.
+ *
+ * Reader logic should follow this sketch:
+ *
+ *		for (;;)
+ *		{
+ *			int before_ct, after_ct;
+ *
+ *			pgstat_begin_read_activity(beentry, before_ct);
+ *			... copy beentry data to local memory ...
+ *			pgstat_end_read_activity(beentry, after_ct);
+ *			if (pgstat_read_activity_complete(before_ct, after_ct))
+ *				break;
+ *			CHECK_FOR_INTERRUPTS();
+ *		}
+ *
+ * For extra safety, we generally use volatile beentry pointers, although
+ * the memory barriers should theoretically be sufficient.
+ */
+#define PGSTAT_BEGIN_WRITE_ACTIVITY(beentry) \
+	do { \
+		START_CRIT_SECTION(); \
+		(beentry)->st_changecount++; \
+		pg_write_barrier(); \
+	} while (0)
+
+#define PGSTAT_END_WRITE_ACTIVITY(beentry) \
+	do { \
+		pg_write_barrier(); \
+		(beentry)->st_changecount++; \
+		Assert(((beentry)->st_changecount & 1) == 0); \
+		END_CRIT_SECTION(); \
+	} while (0)
+
+#define pgstat_begin_read_activity(beentry, before_changecount) \
+	do { \
+		(before_changecount) = (beentry)->st_changecount; \
+		pg_read_barrier(); \
+	} while (0)
+
+#define pgstat_end_read_activity(beentry, after_changecount) \
+	do { \
+		pg_read_barrier(); \
+		(after_changecount) = (beentry)->st_changecount; \
+	} while (0)
+
+#define pgstat_read_activity_complete(before_changecount, after_changecount) \
+	((before_changecount) == (after_changecount) && \
+	 ((before_changecount) & 1) == 0)
+
+
+/* ----------
+ * LocalPgBackendStatus
+ *
+ * When we build the backend status array, we use LocalPgBackendStatus to be
+ * able to add new values to the struct when needed without adding new fields
+ * to the shared memory. It contains the backend status as a first member.
+ * ----------
+ */
+typedef struct LocalPgBackendStatus
+{
+	/*
+	 * Local version of the backend status entry.
+	 */
+	PgBackendStatus backendStatus;
+
+	/*
+	 * The xid of the current transaction if available, InvalidTransactionId
+	 * if not.
+	 */
+	TransactionId backend_xid;
+
+	/*
+	 * The xmin of the current session if available, InvalidTransactionId if
+	 * not.
+	 */
+	TransactionId backend_xmin;
+} LocalPgBackendStatus;
+
+/*
+ * Working state needed to accumulate per-function-call timing statistics.
+ */
+typedef struct PgStat_FunctionCallUsage
+{
+	/* Link to function's hashtable entry (must still be there at exit!) */
+	/* NULL means we are not tracking the current function call */
+	PgStat_FunctionCounts *fs;
+	/* Total time previously charged to function, as of function start */
+	instr_time	save_f_total_time;
+	/* Backend-wide total time as of function start */
+	instr_time	save_total;
+	/* system clock as of function start */
+	instr_time	f_start;
+} PgStat_FunctionCallUsage;
+
+
+/* ----------
+ * GUC parameters
+ * ----------
+ */
+extern PGDLLIMPORT bool pgstat_track_activities;
+extern PGDLLIMPORT bool pgstat_track_counts;
+extern PGDLLIMPORT int pgstat_track_functions;
+extern PGDLLIMPORT int pgstat_track_activity_query_size;
+extern char *pgstat_stat_directory;
+extern char *pgstat_stat_tmpname;
+extern char *pgstat_stat_filename;
+
+/*
+ * BgWriter statistics counters are updated directly by bgwriter and bufmgr
+ */
+extern PgStat_MsgBgWriter BgWriterStats;
+
+/*
+ * Updated by pgstat_count_buffer_*_time macros
+ */
+extern PgStat_Counter pgStatBlockReadTime;
+extern PgStat_Counter pgStatBlockWriteTime;
+
+/* ----------
+ * Functions called from postmaster
+ * ----------
+ */
+extern Size BackendStatusShmemSize(void);
+extern void CreateSharedBackendStatus(void);
+
+extern void pgstat_init(void);
+extern int	pgstat_start(void);
+extern void pgstat_reset_all(void);
+extern void allow_immediate_pgstat_restart(void);
+
+#ifdef EXEC_BACKEND
+extern void PgstatCollectorMain(int argc, char *argv[]) pg_attribute_noreturn();
+#endif
+
+
+/* ----------
+ * Functions called from backends
+ * ----------
+ */
+extern void pgstat_ping(void);
+
+extern void pgstat_report_stat(bool force);
+extern void pgstat_vacuum_stat(void);
+extern void pgstat_drop_database(Oid databaseid);
+
+extern void pgstat_clear_snapshot(void);
+extern void pgstat_reset_counters(void);
+extern void pgstat_reset_shared_counters(const char *);
+extern void pgstat_reset_single_counter(Oid objectid, PgStat_Single_Reset_Type type);
+extern void pgstat_reset_slru_counter(const char *);
+
+extern void pgstat_report_autovac(Oid dboid);
+extern void pgstat_report_vacuum(Oid tableoid, bool shared,
+								 PgStat_Counter livetuples, PgStat_Counter deadtuples);
+extern void pgstat_report_analyze(Relation rel,
+								  PgStat_Counter livetuples, PgStat_Counter deadtuples,
+								  bool resetcounter);
+
+extern void pgstat_report_recovery_conflict(int reason);
+extern void pgstat_report_deadlock(void);
+extern void pgstat_report_checksum_failures_in_db(Oid dboid, int failurecount);
+extern void pgstat_report_checksum_failure(void);
+
+extern void pgstat_initialize(void);
+extern void pgstat_bestart(void);
+
+extern void pgstat_report_activity(BackendState state, const char *cmd_str);
+extern void pgstat_report_tempfile(size_t filesize);
+extern void pgstat_report_appname(const char *appname);
+extern void pgstat_report_xact_timestamp(TimestampTz tstamp);
+extern const char *pgstat_get_wait_event(uint32 wait_event_info);
+extern const char *pgstat_get_wait_event_type(uint32 wait_event_info);
+extern const char *pgstat_get_backend_current_activity(int pid, bool checkUser);
+extern const char *pgstat_get_crashed_backend_activity(int pid, char *buffer,
+													   int buflen);
+
+extern void pgstat_progress_start_command(ProgressCommandType cmdtype,
+										  Oid relid);
+extern void pgstat_progress_update_param(int index, int64 val);
+extern void pgstat_progress_update_multi_param(int nparam, const int *index,
+											   const int64 *val);
+extern void pgstat_progress_end_command(void);
+
+extern PgStat_TableStatus *find_tabstat_entry(Oid rel_id);
+extern PgStat_BackendFunctionEntry *find_funcstat_entry(Oid func_id);
+
+extern void pgstat_initstats(Relation rel);
+
+extern char *pgstat_clip_activity(const char *raw_activity);
+
+/* ----------
+ * pgstat_report_wait_start() -
+ *
+ *	Called from places where server process needs to wait.  This is called
+ *	to report wait event information.  The wait information is stored
+ *	as 4-bytes where first byte represents the wait event class (type of
+ *	wait, for different types of wait, refer WaitClass) and the next
+ *	3-bytes represent the actual wait event.  Currently 2-bytes are used
+ *	for wait event which is sufficient for current usage, 1-byte is
+ *	reserved for future usage.
+ *
+ * NB: this *must* be able to survive being called before MyProc has been
+ * initialized.
+ * ----------
+ */
+static inline void
+pgstat_report_wait_start(uint32 wait_event_info)
+{
+	volatile PGPROC *proc = MyProc;
+
+	if (!pgstat_track_activities || !proc)
+		return;
+
+	/*
+	 * Since this is a four-byte field which is always read and written as
+	 * four-bytes, updates are atomic.
+	 */
+	proc->wait_event_info = wait_event_info;
+}
+
+/* ----------
+ * pgstat_report_wait_end() -
+ *
+ *	Called to report end of a wait.
+ *
+ * NB: this *must* be able to survive being called before MyProc has been
+ * initialized.
+ * ----------
+ */
+static inline void
+pgstat_report_wait_end(void)
+{
+	volatile PGPROC *proc = MyProc;
+
+	if (!pgstat_track_activities || !proc)
+		return;
+
+	/*
+	 * Since this is a four-byte field which is always read and written as
+	 * four-bytes, updates are atomic.
+	 */
+	proc->wait_event_info = 0;
+}
+
+/* nontransactional event counts are simple enough to inline */
+
+#define pgstat_count_heap_scan(rel)									\
+	do {															\
+		if ((rel)->pgstat_info != NULL)								\
+			(rel)->pgstat_info->t_counts.t_numscans++;				\
+	} while (0)
+#define pgstat_count_heap_getnext(rel)								\
+	do {															\
+		if ((rel)->pgstat_info != NULL)								\
+			(rel)->pgstat_info->t_counts.t_tuples_returned++;		\
+	} while (0)
+#define pgstat_count_heap_fetch(rel)								\
+	do {															\
+		if ((rel)->pgstat_info != NULL)								\
+			(rel)->pgstat_info->t_counts.t_tuples_fetched++;		\
+	} while (0)
+#define pgstat_count_index_scan(rel)								\
+	do {															\
+		if ((rel)->pgstat_info != NULL)								\
+			(rel)->pgstat_info->t_counts.t_numscans++;				\
+	} while (0)
+#define pgstat_count_index_tuples(rel, n)							\
+	do {															\
+		if ((rel)->pgstat_info != NULL)								\
+			(rel)->pgstat_info->t_counts.t_tuples_returned += (n);	\
+	} while (0)
+#define pgstat_count_buffer_read(rel)								\
+	do {															\
+		if ((rel)->pgstat_info != NULL)								\
+			(rel)->pgstat_info->t_counts.t_blocks_fetched++;		\
+	} while (0)
+#define pgstat_count_buffer_hit(rel)								\
+	do {															\
+		if ((rel)->pgstat_info != NULL)								\
+			(rel)->pgstat_info->t_counts.t_blocks_hit++;			\
+	} while (0)
+#define pgstat_count_buffer_read_time(n)							\
+	(pgStatBlockReadTime += (n))
+#define pgstat_count_buffer_write_time(n)							\
+	(pgStatBlockWriteTime += (n))
+
+extern void pgstat_count_heap_insert(Relation rel, PgStat_Counter n);
+extern void pgstat_count_heap_update(Relation rel, bool hot);
+extern void pgstat_count_heap_delete(Relation rel);
+extern void pgstat_count_truncate(Relation rel);
+extern void pgstat_update_heap_dead_tuples(Relation rel, int delta);
+
+struct FunctionCallInfoBaseData;
+extern void pgstat_init_function_usage(struct FunctionCallInfoBaseData *fcinfo,
+									   PgStat_FunctionCallUsage *fcu);
+extern void pgstat_end_function_usage(PgStat_FunctionCallUsage *fcu,
+									  bool finalize);
+
+extern void AtEOXact_PgStat(bool isCommit, bool parallel);
+extern void AtEOSubXact_PgStat(bool isCommit, int nestDepth);
+
+extern void AtPrepare_PgStat(void);
+extern void PostPrepare_PgStat(void);
+
+extern void pgstat_twophase_postcommit(TransactionId xid, uint16 info,
+									   void *recdata, uint32 len);
+extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
+									  void *recdata, uint32 len);
+
+extern void pgstat_send_archiver(const char *xlog, bool failed);
+extern void pgstat_send_bgwriter(void);
+
+/* ----------
+ * Support functions for the SQL-callable functions to
+ * generate the pgstat* views.
+ * ----------
+ */
+extern PgStat_StatDBEntry *pgstat_fetch_stat_dbentry(Oid dbid);
+extern PgStat_StatTabEntry *pgstat_fetch_stat_tabentry(Oid relid);
+extern PgBackendStatus *pgstat_fetch_stat_beentry(int beid);
+extern LocalPgBackendStatus *pgstat_fetch_stat_local_beentry(int beid);
+extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
+extern int	pgstat_fetch_stat_numbackends(void);
+extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
+extern PgStat_GlobalStats *pgstat_fetch_global(void);
+extern PgStat_SLRUStats *pgstat_fetch_slru(void);
+
+extern void pgstat_count_slru_page_zeroed(int slru_idx);
+extern void pgstat_count_slru_page_hit(int slru_idx);
+extern void pgstat_count_slru_page_read(int slru_idx);
+extern void pgstat_count_slru_page_written(int slru_idx);
+extern void pgstat_count_slru_page_exists(int slru_idx);
+extern void pgstat_count_slru_flush(int slru_idx);
+extern void pgstat_count_slru_truncate(int slru_idx);
+extern const char *pgstat_slru_name(int slru_idx);
+extern int	pgstat_slru_index(const char *name);
+
+#endif							/* PGSTAT_H */